My
concern about the 100m OM3 reach is not with access layer switch to server
connections, which are shorter with higher density servers, but with backbone
connectivity (switch-to-switch connectivity).

Conversion
to high density servers doesn’t affect distances from the switches located in
Main Distribution Area / Main Distributor (the core of the data center
infrastructure) to the switches located in the Horizontal Distribution Area /
Zone Distributor (commonly one per row). These distances are affected only by
the physical dimensions of a data center and location of the Main Distribution
Area / Main Distributor, which is hopefully, but not always near the physical
center of the data center.

While I am
sympathetic with your view of the objectives, I disagree and oppose changing
the current reach objective of 100m over OM3 fiber.

From my
previous standards experience, I believe that all the difficulties arise in the
last 0.5 dB or 1dB of the power budget (as well as jitter budget). It is
worthwhile to ask module vendors how much would their yield improve if they are
given 0.5 or 1 dB. It is responsible for most yield hits, making products much
more expensive. I believe that
selecting specifications that penalize 95% of the customers to benefit 5% is a
wrong design point.

You make
another point - that larger data centers have higher bandwidth needs. While it
is true that the bandwidth needs increase, you fail to mention is that the
distance needs today are less than on previous server generations, since the
processing power today is much more densely packed than before.

I believe that
100m is more than sufficient to address our customers' needs.

I am a consultant with over 25 years
experience in data centerinfrastructure design and data center relocations including in excess of 50data centers totaling 2 million+ sq ft. I am currently engaged in
datacenter projects for one of the two top credit card processing firms and oneof the two top computer manufacturers.

I'm concerned about the 100m OM3 reach objective, as it does not cover anadequate number (>95%) of backbone (access-to-distribution anddistribution-to-core switch) channels for most of my clients' data centers.

Based on a review of my current and past projects, I expect that a 150m orlarger reach objective would be more suitable. It appears that some
of thedata presented by others to the task force, such as Alan Flatman's DataCentre Link Survey supports my impression.

There is a pretty strong correlation between the size of my clients' datacenters and the early adoption of new technologies such as higher speed LANconnectivity. It also stands to reason that larger data centers havehigher bandwidth needs, particularly at the network core.

I strongly encourage you to consider a longer OM3 reach objective than
100m.